Electrical protective apparatus.



PATENTED 0017.3, 1905. c. A. ROLPE.

ELECTRICAL PROTECTIVE APPARATUS.

APPLICATION FILED FEB. 18. 1903.

xix N 27137265565: 6% CVZQ/ Z65 11.9092.

flu 612501:

UNITED STATES PATENT OFFICE.

CHARLES A. ROLFE, OF ADRIAN, MICHIGAN, ASSIGNOR, BY MESNE ASSIGNMENTS, TO ROLFE ELECTRIC CO., OF ROCHESTER, NEW YORK, A CORPORATION OF NEWV YORK.

Specification of Letters Patent.

Patented. Oct. 3, 1905.

Application filed February 13, 1903. Serial No. 143,224.

To all whom it may concern:

Be itknown that LCHARLns A. ROLFE, acitizen of the United States, residing at Adrian, in the county of Lenawee and State of Michigan, have invented a certain new and useful Improvement in Electrical Protective Apparatus, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to electrical protective apparatus for protecting electrical circuits from unduly-strong currents and excessively-high potentials.

The object of my presentinvention is to provide a simple, practical, and eflicient device of this kind.

In the accompanying drawings I show my present invention embodied in a device which is intended to be used where there is but one electrical circuit to be protectedas, for example, the subscribers end of a telephone-circuit. The protector herein may therefore be considered or called an individual protector as opposed to a bank or group of protectors associated together.

In the accompanying drawings, Figure 1 is a front elevation of an individual protector embodying my present invention. Fig. 2 is a plan view of the device with the glass cover removed. Fig. 3 is a vertical section taken on line 3 3 in Fig. 2, the cover, however, being in place in Fig. 3. views of a portion of the device.

The protector shown in the drawings for carrying out the invention comprises a base 1, which can be of any suitable insulating material as, for example, porcelain-and a glass dome or cover 2 is arranged upon the base 1. The latter is provided with a central post 3, which rises therefrom and is threaded at its upper end, so as to engage a thumb-nut 4 to hold the glass dome in place. The instrument shown is intended for a metallic circuit and to such end is provided with two protective devices, one for each side of the circuit. Each protective device consists of a pair of springs or spring-posts 5 and 6, which are secured to the base 1,- as by screws 7 and 8, and rise suitably from the base. These posts 5 and 6 tend to spring away or separate from one another. Each spring has its upper end forked or bifurcated, as shown in Fig. 1.

Figs. 4 and 5 are Each pair of springs 5 6 supports and holds in position a device which is known in the trade and may be conveniently called a heat-cartridge. This is shown alone in Figs. 4 and 5.

Each cartridge consists of a small cylinder 9, of insulating material, such as ebonite or vulcanized rubber, provided at its ends with caps 10 and 11. The cap 10 is constructed with an annular groove or channel 12, form ing a head 13 at its end. The cap 11 has its outer end contracted laterally and slotted or forked, so as to form two cars 14 14, Fig. 5, between which a small bell-crank lever 15 is pivoted on a pin 16. One of the cars 14 is provided with an aperture 17, and a small quantity 17 of solder is arranged between the ears 1A 14: and associated with the bell-crank lever 15, so as to hold the latter in place. A spring 18 is secured, as by a screw 19, t0 the cylinder 9 and extended over the cap 11, so as to rest and press upon one arm of the bellcrank lever 15. The lower end of the lever projects below the cap 11. The end portion of the cylinder 9 is transversely bored, and a small stick or pencil 20 of high-resistance graphite is arranged in such bore or aperture. Its upper end is in contact with a small enlarged portion 21 of the cap 11, and its lower end is in contact with and supported by a spring 22, secured by a screw 23 to the cap 10. The stick or pencil 20 of graphite has such a high resistance as to become heated by the passage in the circuit of an unduly-strong current, and when it is so heated it melts the solder holding the lever 15 in place.

When the cartridges are in position in the protector, the springs 5 5 are engaged by the heads 13 13 of the cartridges and the springs 6 6 are engaged by the lower ends of the levers 15 15 of the same. In the rear of the springs 5 5 is a smaller and supplemental post 24:, carrying at its end a pivoted cross-bar 25, which is free to vibrate a slight distance, as permitted by the springs 5 5. On the other side of the post 24 is located a lightning-arrester arrangement consisting of a pair of linesprings 26 26, a ground-plate 27 and a pair of carbons 28 28, having insulating-strips 28 28*, each carbon with its strip being located between a line-spring 26 and the groundplate 27.

The base 1 is provided with apertures 29 29, 30 30, and 31, which are for the various con- TOO ductors to be connected with the instrument. The instrument-conductors 32 32, which are understood to run to the instrument, pass through the apertures 29 29 and are connected. to the base of the springs 6 6. The line conductors 33 33 extend up through the apertures 30 30 and are connected at the base of the springs 5 5. A ground-conductor 34; extends through the aperture 31 and is connected to the ground-plate 27.

The operation of the instrument is as follows: When the circuitis in normal condition and the usual small current is passingover it, the instrument is in the condition shown in Figs. 1 and 2 and in the full lines in Fig. 3. hen, however, an abnormally large current traverses the circuit, one or both of the graphite sticks 20 in the heat-cartridges become heated, thereby softening the solder of one or both of said cartridges and releasing the lever or levers 15 thereof. 11 but one cartridge operates, the spring 6, held in restraint thereby, becomes freed from the lever 15 and moves the spring outwardly, as shown in dotted lines in Fig. 3. By this action it becomes freed from the lever 15, thereby breaking or opening the circuit at its end. At the same time the spring 5 springs outwardly and strikes against the swinging bar 25, causing the latter to turn and strike against theother spring 5, thereby shunting or closing the line through the instrument. If both cartridges operate, both the springs 6 6 will be released and the circuit opened at their ends and both springs 5 5 will swing backward against the shuntbar 25 with the same result as before/that is, closing the line through the protector. Thus in both cases, whether either one or both of the cartridges operate, the circuit to the instrument to be protected is opened and the lineis shunted or closed. After either cartridge operates its spring 18 will swingits lever 15 back to normal or original position while the solder is still soft, thus automatically restoring itto operative condition. As soon as the solder hardens the spring or springs 6 can be reengaged with the operated cartridge or cartridges, again placing the protector in condition to operate. The lightning-ar-rester arrangement, it will be seen, can operate in the usual way, a lightning discharge passing from either of the line-springs 26 26 to the groundplate 27 and thence to ground in the usual way.

Certain features of this invention, notably the graphite as a heat-concentrating device and the arrangement by which the cartridge is automatically restored to operative condition, are embodied alonein other applications of mine now on tile in the Patent ()tfice, and hence are not claimed alone in this application.

In another application filed by me of even date herewith, Serial No. 143,225, 1 have shown a bank protective system embodying the broader features of the invention herein set forth, and in said other application I claim said invention broadly, conlining the claims in the present application to the specilic construction and general arrangement of the device shown herein, where it ditlers t'rom the construction of my said other application.

\V hat 1 claim as my invention is 1. In a device of the class specified, the combination of a pair of protective devices, one for each side of the circuit, each protective device containing a spring adapted to be released upon the operation of said device, and a swinging bar for short-circuiting the circuit adapted to be actuated by either of said springs to swing it against the other, substantially as described.

2. In adevice of the class specified, the com bination of a pair of protective devices, each containing a spring normally held in restraint, but released when the protective device operates, a swinging bar arranged in thercar of said springs and pivoted between the same, each of the springs being adapted to come in contact with the bar when released, substantially as described.

3. In a device of the class specified, a cartridge consisting of a body of insulating material, metallic caps at the ends of the same, a small piece of graphite supported atone end of said body in contact with the cap at that end, a bell-crank lever also supported by said cap, a spring secured to the insulating-body and acting upon one of the arms of said bellcrank lever to restore the same to operative position, and a contact connecting the other cap with the other end of the graphite stick, substantially as described.

1. In a device of the class specified, a cartridge consisting of a body 9 of insulating material, a cap 10 having a head 13 at one end of said body 9, a cap 11 at the other end of the same, a graphite stick 20 extended through the body 9 and having one of its ends in contact with the cap 11, a contact 22 extended between the cap 10 and the graphite stick 20, the cap 11 being constructed with ears 1 1, 1 1, a bell-crank lever 15 arranged between said ears and pivoted upon a pin 16, solder holding said lever in position, and a spring 18 tending to restore the lever 15 to original position, substantially as described.

5. A device of the class specified, comprising a pair of protective devices each consist ing of a pair of springs, l1eat-cartri :lges supported by said springs and holding the same in restraint, each of said cartridges being adapted to act imlependently upon the passage through it of an unduly-strong current, a swinging bar in the rear of two corresponding springs of said protective devices and pivoted between said springs, each of said springs being adapted to make contact with said bar when released, substantially as described.

6. A device of the class specified, comprising a pair of protective devices each consisting of springs 5 and 6, a cartridge comprising a body of insulating material having its ends provided with connecting devices for engaging said springs, a stick of graphite supported by said insulating-body, said stick being in contact with one connecting device and connected with the other, and a pivoted bar in the rear of the springs 5, 5, pivoted between the same substantially as described.-

7 1n a device of the class specified, a cartridge consisting of a body of insulating material having its ends provided with metallic connecting devices, a stick of graphite carried by said insulating body and having one'of its ends in contact with one of said connecting devices, and means for connecting the graphite with the other of said connecting devices, substantially as described.

8. An electrical-circuit protector, comprising a pair of electrical protective devices arranged side by side, each of said devices having provisions whereby it is automatically restored to operative condition, and means for short-circuiting the circuit on the operation of either of said devices.

9. An electrical-circuit protector, comprising a pair of solder-joint protective devices arranged side by side, each of which devices has provisions whereby after operation it is automatically resoldered preparatory for another operation, and means for short-circuiting the circuit upon operation of either of said devices.

10. An electrical-circuit protector, comprising a pair of solder-joint protective devices, each having provisions for automatically resoldering itself in operative condition, and a swinging bar pivoted between said devices for automatically short-circuiting the circuit on the operation of either one thereof.

11. An electrical-circuit protector, comprising a pair of protective devices, each consisting of a solderjoint heat-cartridge having provisions for automatically resoldering itself in operative condition, and supporting members for said cartridge, one of which is a spring, and a metallic bar pivoted between said protective devices and arranged to make connection with the same on the operation of either one thereof.

In witness whereof I hereunto subscribe my name this 22d day of January, A. D. 1903.

CHARLES A. ROLFE.

WVitnesses:

A. MILLER BELFIELD, I. C. LEE. 

